37 lines
720 B
C
37 lines
720 B
C
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#include "nrutil.h"
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void voltra(n,m,t0,h,t,f,g,ak)
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float (*ak)(),(*g)(),**f,*t,h,t0;
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int m,n;
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{
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void lubksb(),ludcmp();
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int i,j,k,l,*indx;
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float d,sum,**a,*b;
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indx=ivector(1,m);
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a=matrix(1,m,1,m);
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b=vector(1,m);
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t[1]=t0;
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for (k=1;k<=m;k++) f[k][1]=(*g)(k,t[1]);
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for (i=2;i<=n;i++) {
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t[i]=t[i-1]+h;
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for (k=1;k<=m;k++) {
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sum=(*g)(k,t[i]);
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for (l=1;l<=m;l++) {
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sum += 0.5*h*(*ak)(k,l,t[i],t[1])*f[l][1];
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for (j=2;j<i;j++)
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sum += h*(*ak)(k,l,t[i],t[j])*f[l][j];
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a[k][l]=(k == l)-0.5*h*(*ak)(k,l,t[i],t[i]);
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}
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b[k]=sum;
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}
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ludcmp(a,m,indx,&d);
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lubksb(a,m,indx,b);
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for (k=1;k<=m;k++) f[k][i]=b[k];
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}
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free_vector(b,1,m);
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free_matrix(a,1,m,1,m);
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free_ivector(indx,1,m);
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}
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